Wireless and mobile network operators face the continuing challenge of building networks that effectively manage high data-traffic growth rates. Mobility and an increased level of multimedia content for end users requires end-to-end network adaptations that support both new services and the increased demand for broadband and flat-rate Internet access. In addition, network operators must consider the most cost-effective evolution of the networks towards 4G and other advanced network capabilities. Wireless and mobile technology standards are evolving towards higher bandwidth requirements for both peak rates and cell throughput growth. The latest standards supporting these higher bandwidth requirements are HSPA+, WiMAX, TD-SCDMA and LTE. The network upgrades required to deploy networks based on these standards must deal with the limited availability of new spectrum, leverage existing spectrum, and ensure operation of all desired wireless technology standards. The processes of scarce resource optimization while ensuring a future-proof implementation must both take place at the same time during the transition phase, which usually spans many years and thus can encompass numerous future developments. Distributed open base station architecture concepts have evolved in parallel with the evolution of the various technology standards to provide a flexible, lower-cost, and more scalable modular environment for managing the radio access evolution. Such advanced base station architectures can generally be appreciated from FIG. 1 [PRIOR ART], which shows an architecture for a prior art Distributed Wireless Network Base Station. In FIG. 1, 100 is a depiction of a Distributed Wireless Network Base Station. The Base Transceiver Station (BTS) or Digital Access Unit (DAU) 101 coordinates the communication between the Remote Radio Head Units 102, 103 and the Base Station Controller (BSC). The BTS communicates with multiple Remote Radio Heads via optical fiber. For example, the Open Base Station Architecture Initiative (OBSAI), the Common Public Radio Interface (CPRI), and the IR Interface standards introduced publicly-defined interfaces separating the Base Transceiver Station (BTS) or Digital Access Unit and the remote radio head unit (RRU) parts of a base station by employing optical fiber transport.
The RRU concept constitutes a fundamental part of an advanced state-of-the-art base station architecture. RRU-based system implementation is driven by the need to achieve consistent reductions in both Capital Expenses (CAPEX) and Operating Expenses (OPEX), and enable a more optimized, energy-efficient, and greener base deployment. An existing application employs an architecture where a 2G/3G/4G base station is connected to RRUs over multiple optical fibers. Either CPRI, OBSAI or IR Interfaces may be used to carry RF data to the RRUs to cover a sectorized radio network coverage area corresponding to a radio cell site. A typical implementation for a three-sector cell employs three RRU's. The RRU incorporates a large number of digital interfacing and processing functions. However, commercially available RRU's are power inefficient, costly and inflexible. Their poor DC-to-RF power conversion insures that they will need to have a large mechanical housing to help dissipate the heat generated. The demands from wireless service providers for future RRU's also includes greater flexibility in the RRU platform, which is not presently available. As standards evolve, there will be a need for multi-band RRUs that can accommodate two or more operators using a single wideband power amplifier. Co-locating multiple operators in one DAS system would reduce the infrastructure costs and centralize the Remote Monitoring Function of multiple Operators on the Network. To accommodate multiple operators and multiple bands per operator would require a very high optical data rate to the RRUs which is not achievable with prior art designs.